overheading

1985 mb 500SEL; overheading above 100c; removed thermostat; still over heats between 100c and 120c.
Any suggestions. Is the fan supposed to run at one speed no matter how
fast the RPM is?
Could the radiator be plugged?
Could the water pump be not producing enough pressure?
Help.
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First question, does it run hot at highway speed? Does it only get hot when idleing? Or both?

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Both, I can let it idle for some time or drive it and it reaches to the 120 and would go over 120 if I did not turn around and come back home.
Patrick
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PUT the thermostat back in. Without it, the water flows too fast to cool off. The thermostat must be in to restrict the flow. Turn the defroster on; full heat full blower. Does the temp go down? If yes, replace the radiator. If no, did the impeller come off the water pump shaft?

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Never run car without thermostat! First thing I would do is put a new thermostat in.
Then I would buy a infrared thermometer and check the actual temperature at the brass sensor on the thermostat housing. Check that reading against the dash.
Alot of time, I find that the dash reading is off due to age.
Main engine fan on that year is a constant speed type. Later model year goes faster according to temp but yield no difference in cooling. I tried.
Clean your radiator fins by backflushing it with air or water... from engine bay outward to bumper.
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I took the guts out of the thermostat to see if it would run cooler. Did this on my 49 Chevy Fastback and 53 fords. They ran well for years. I also did this on a 64 Tbird and it always ran well within the range of the temperature back and forth to LA.
Yes I checked the temperature with a digital thermo to see if it was really over 100C. And it was.
Do you think the radiator is clogged?
Patrick
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Yabbut this is not a 49 Ford.

Sure sounds like it. Flush with liquid tide and then citric acid. Refill with the proper mix of coolant and water. If it's still too hot add some Redline water wetter.
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This is not a single direction flow thermostat like typical american car cooling system. This is dual stage dual direction multipath cooling system.
Put a new one in.
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